Centrifuge with auxiliary feed arrangement



Feb. 10, 1953 P. H. STAAFF CENTRIFUGE WITH AUXILIARY FEED ARRANGEMENT Filed Aug. 21 L950 INVENTOR.

PEr'W Patented Feb. 10, 1 953 CENTRIFUGE WITH AUXILIARY FEED ARRANGEMENT Per Hilding Staaif, Alsten, Sweden, assignor to Aktiebolaget Separator, Stockholm, Sweden, a corporation of Sweden Original application May 3, 1949, Serial No.

91,128. Divided and this application August Serial No. 180,586 In Sweden May 3,

9 Claims. (Cl. 233-14) This invention relates to centrifuges and more particularly to an improved centrifugal separator of the type having provision for feeding an auxiliaryv liquid into the outer peripheral portion of the centrifugal bowl, independently of the original feed, to assist in the operation of the centrifuge.

Thi application is a division of my co-pending application Serial No. 91,128, filed May 3, 1949; now Patent No. 2,526,292.

Centrifuges of the above-mentioned type are well-known and have been used toadvantage under certain conditions. For example, when the material to be separated includes a sludge component which tends to clog the sludge outlets in the outer periphery of the bowl, this tendency can be overcome by enlarging the sludge outlets and recirculating some of the discharged sludge component to the bowl atthe region of these outlets, whereby a relatively high rate of flow can be maintained in the sludge outlets without discharging a lighter component or components.

in excessive amounts through such outlets. Also,

when recirculated sludge-containing liquid is.

thus used as the auxiliary liquid, it is possible to regulate the concentration of the sludge component discharging through the peripheral outlets by simply adjusting the rate of recirculation. In some cases, the auxiliary liquid consists of water for effecting a washing operation in the outer part of the bowl concurrently with the separation, or it may consist of someother liquid or a mixture of the sludge component and another liquid. Y.

In centrifuges of the auxiliary feedtype, various arrangements have been used heretofore to feed the auxiliary liquid to th outer part of the bowl. However, these prior arrangements,

for the most part,'have not been entirely satis-" factory, due to the resulting complexity .of the bowl structure (particularly wheniit. is necessary to. provide separate .outlets forthree separated components), or to impairment of the separating. operation, or to leakage of the auxiliary liquid from its supply path,'or to a combination of these reasons. l

The present invention has for its principal object the provision of a centrifugal separator of the character described, which overcome the above-mentioned objections.:. a

Another object is to provide a centrifuge of the separated sludge component constituting the heaviest of three component into which the feed is separated in'the chamber. A light component outlet, which is preferably located on the bowl axis, leads from within a conical disc in the upper part ofthe bowl. Above this conical disc is a similar disc, and above the latter is another conical member, which may be the bowl top. These three conical members are spaced from each other to define a pair of conical interspaces separated by the intermediate member, the interspaces being subdivided, if desired, by ribs. One of the conical interspaces, preferably the upper one. leads from the outer part of the separating chamber to an outlet through which the intermediate component is discharged from the bowl, while the other leads to the peripheral part of the chamber from an auxiliary feed port of the bowl communicating with a stationary feed pipe for an auxiliary liquid. Thus, the auxiliary liquid is delivered to the outer region of the separating chamber in a relatively thin annular layer adjacent to but separated from imilar layers of the intermediate and light components, which discharge separately along the conical members countercurrently to the flow of the auxiliary liquid. The conical interspace for feeding the auxiliary liquid allows the latter to be distributed uniformly around the outer rating chamber.

The preferred construction of the new centrifuge is as follows: The lowermost of the three gconical members tapers upward to a neck or tube projecting axially from the bowl into a seal through which it communicates with a stationary 1 .19. closed path out of contactwith atmosphere,

region of the sepawhich I find to be particularly advantageous in concentrating sour cream for the production of butter, as disclosed in my previously mentioned co-pending application. The stationary feed pipe for the auxiliary liquid is sealed around the axial neck or tube and also around an extension of the intermediate conical member, thereby forming a closed path through which the auxiliary liquid is fed into the interspace between the intermediate and the lower conical member.

For a better inderstanding of the invention, reference may be had to the accompanying drawing in which the single illustration is a vertical sectional view of a preferred form of the new centrifuge, showing diagrammatically a system for recirculating separated sludge to the centrifugal bowl as the auxiliary liquid. 7

Referring to the drawing, the centrifuge comprises a hollow spindle l which supports and rotates a centrifugal bowl 2. Within the separating chamber of the bowl 2 is a stack of conical discs 2a, the discs being spaced from each other in the usual manner. The discs are provided with axial openings through which a center-post 21) extends upwardly from the lower portion of the bowl, whereby the discs are centered in the separating chamber. The center-post 2b has an expanded lower portion 20 resting upon the bot tom of the bowl and forming an inlet chamber 2d into which the original feed material is delivered by way of a central passage in in the spindle l. A hollow tube 2e projects inwardly toward the rotation axis of the bowl from the wall of the expanded portion 20, so as to afford communication between the inletchamber 2d and the main separating chamber containing the discs 2a. Thus, the spindle passage la, feed chamber 20'. and tube 2e form an inlet for delivering to the main separating chamber the material to be separated. In the passage of the material through the .feed chamber 2d, some of the heavier fraction, such as impurities or sludge, is collected in the outer part of the feed chamber under the action of centrifugal force, the remainder of the material being delivered through the tube 26 to distributing holes 2f in the conical discs in the main separating chamber. Preferably, the expanded portion 2c is provided with at least three tubes 26 spaced vequidistantly about the rotation axis and each leading to a set of distributing holes 2 finthe discs.

.At the upper portion of the bowl z is a pair of superimposed conical members 2g and 3, the member 2 forming the bowl top. Theseconical members are located above a conical top disc 4 supported on the center-post 2b and forming the upper confine of the separating chamber. The conical members 2g3 and the top disc :3 are spaced from each other to form a pair of superimposed .conical interspaces 3a and ta separated by the conical member 3. At its upper or reduced portion, the conical top disc 4 terminates in ahollow tube 4b projecting axially from the bowl and forming a light component outlet to. This outlet'leads from within the conical top disc 4 by way of a recess 2h in the upper portion of the center-post 2b.

Aneck extension .5 is secured on top of the conical members 29 and 3 and forms with the member 29 a series of radial outlets So for an intermediate component separated in the bowl. The upper conical intcrspace 30: leads inward and upward with a taper to the intermediate component outlets 5a from the outer part 22 of the separating chamber, that is, the outer zone of the chamber beyond the discs 2a. The neck extension 5 has a cylindrical portion surrounding the hollow tube 4b in spaced relation thereto and forming therewith an axial feed port 5b. From this feed .port 527, which is of annular form surrounding th tube 4b, the lower conical interspace 4a leads outward and downward with a flare to the outer portion 21' of the separating chamber.

The hollow spindle l is rotatably mounted in any suitable manner in a stationary structure including a hollow frame 6 having a collecting chamber 6a. The latter receives the sludge or heavy component separated in the bowl 2, this component being discharged from the outer portion 22' of the bowl chamber through peripheral outlets 2 into the stationary chamber Go. From chamber 6, the heavy component is led through an outlet 6b into a receptacle l, where the sludge is allowed to settle toward the bottom of the container. Part of the sludge-containing liquid is withdrawn from the system over a level outlet 8. By means of a pump 9 and a duct ill, the remaining part of the sludge-containing liquid is recirculated to the bowl through a stationary auxiliary feed pipe ll.

The feed pipe H has asealed connection atfording communication between this .pipe and the auxiliary feed port 5b of the bowl. .Asillustra'ted. an annular seal llais located between the wall of the feed pipe I l and the neck extension '5,.and a second annular seal llb is located between the wall of pipe ll andthe auxiliary tube ib. In other words, the feed pipe ll terminates in .a cylindrical portion surrounding the tube 4?) and the upper part of the neck extension 5, and the ring Ila forms a seal between the extension 5 and the lower part of this cylindrical portion, while the ring 'Hb forms a seal between the auxiliary tube and the upper part of this cylindrical portion. Accordingly, theauxiliary liquid is delivered in a closed path from the stationary pipe ll to the auxiliary feed port 5b and thence through the conical interspace 4a to the outer part 2i of the separating chamber. In its passage through the conical interspace 4a,"the auxiliary liquid vflows countercurrently to the intermediate component discharging through the conical interspace -3aand to the light component moving toward the central outlet 40.

When the centrifuge is to be used for concentrating our cream which has been neutralized, as in the production of butter, '1 find that it is advantageous to provide a closed discharge path for the light component or cream separated in the bowl. Thus, the cream discharging through the central passagelc is delivered to a stationary discharge pipe 12 containing an annular seal 12a through which the tube 41) extends. In this way, the cream is rmaintained out of contact with atmosphere as it passes from the rotating bowl' to the stationary discharge pipe I2.

The intermediate component discharged through'the bowl .outletsf5a, isrcollected in an open receptacle l3 mounted on a cover 60 for the stationary frame. From the receptacle 13, the intermediate component .is discharged through an outlet 14.

The operation :of the centrifuge will now be described in connection with the concentration of sour cream which has been neutralized, although it will :be understood that this example of the use-of the centrifuge is'only for "illustrative purposes and that the centrifuge is "not limited to this use. The neutralized cream is fedinto-the spaces between the discs 2a byway of the spindle passage la, feed chamber 2d, tube 2e and-distributing holes 21. In the separating chamber'of the bowl, the cream is separated into three components comprising a heavy or sludge-containing component, an intermediate component which is primarily skim milk, and a light component; which is primarily cream concentrated to a fat content of 80-85%. -The concentrated cream is displaced upwardly and inwardly within the top disc 4 and is discharged from the interiorof this disc at its upper or reduced portion through the closed path formed by the axial tube 421', the seal in, and the pipe I2. The skim milk component, which moves outwardly between the discs 2a, is discharged from the outer part 22' of the separating chamber through the upper conical interspace 3a and the intermediate component outlets 5a. to the stationary receptacle l3. The sludgecontaining liquid or heavy component is discharged through the peripheral outlets 2i, and part of this component is recirculated from the receptacle 1 to the auxiliary feed port 51) by way of the closed path formed by the stationary pipe II and its associated eals Ila and Nb. From the auxiliary feed port 51), the sludge-containing liquid or auxiliary feed passes downwardly and outwardly through the lower conical interspace 4a countercurrently to the discharge of the skim milk and concentrated cream components which are divided from each other and from the auxiliary feed by the two upper cones 3 and 4. By adjusting the rate at which the sludge-containing liquid is delivered to the auxiliary feed pipe II, the concentration of the ludge in the heavy component discharging through the peripheral outlets 2 of the bowl may be adjusted. Also, recirculation of the sludge component, as previously described, enables the use of larger peripheral outlets 2 whereby clogging of these outlets is avoided.

The conical interspaces 3a and 4a may, if desired, be subdivided by radial ribs or wings extending upwardly and inwardly from the outer or peripheral portions of these interspaces. The ribs in the conical interspace 40. may then serve to support the conical member 3 on the top disc 4 in spaced relation thereto.

It will be apparent that the new centrifuge provides an efiicient means for feeding an auxiliary liquid into the outer part of the bowl chamber, without complicating the construction of the centrifuge or interfering with the separating operation. By reason of the conical interspace 4a in the upper part of the bowl, the auxiliary liquid is distributed uniformly around the outer part 22 of the bowl chamber, thereby minimizing the formation of eddy currents in this outer region.

I claim:

1. A centrifugal bowl comprising a bowl shell rotatable about an axis and having a separating chamber, the chamber having an inlet for the material to be separated and a peripheral outlet for a separated heavy component, a conical disc mounted in the upper part of said chamber and forming at its reduced portion a light component outlet leading from within the disc, a pair of superimposed conical members rotatable with the shell and located above and outwardly from the disc, said members and disc being spaced from each other to form a pair of superimposed conical interspaces separated by one of said members, the bowl having an intermediate component outlet to which one of said conical interspaces ward with a flare to the outer part of said chamber.

2.-A centrifugal bowl according to claim 1, in which the conical disc terminates at its reduced.

end in a hollow tube projecting axially from the bowl and forming said light component outlet.

3. A centrifugal bowl according to claim 1, in which the conical disc terminates at its reduced end in a hollow tube projecting axially frompthe bowl and forming said light component outlet,

1 the bowl also comprising a hollow spindle projecting axially from the bottom of the bowl and forming afeed passage for the material to be separated.

4. A centrifugal bowl according to claim 1, in which the outermost of said conical members forms the top of the bowl.

5. A centrifugal bowl according to claim 1, in Which the lowermost of said conical interspaces leads from the auxiliary feed port.

6. A centrifugal bowl according to claim 1, in which the conical disc terminates at its reduced end in a hollow tube projecting axially from the bowl and forming said light component outlet, the auxiliary feed port being of annular form and surrounding and partly formed by said tube.

7. In combination, a centrifugal bowl comprising a bowl shell rotatable about an axis and having a separating chamber, the chamber having an inlet for the material to be separated and a peripheral outlet for a separated heavy component, a conical disc mounted in the upper part of said chamber and terminating at its reduced end in a hollow tube projecting axially from the bowl to form a light component outlet leading from within the disc, a pair of superimposed conical members rotatable with the shell and located above outwardly from the disc, said members and disc'being spaced from each other to form a pair of superimposed conical interspaces separated by one of said members, the bowl hav ing an intermediate component outlet to which one of said conical interspaces leads inward and upward with a taper from the outer part of the separating chamber, a stationary discharge pipe for said light component, a seal between the wall of said pipe and the wall of said tube, and an auxiliary feed port in the bowl surrounding and partly formed by said tube and from which the other conical interspace leads outward and downward with a flare to the outer part of said chamher.

8. A combination according to claim 7, comprising also a neck on the bowl surrounding the tube and defining therewith said port, a stationary feed pipe for an auxiliary liquid. a seal between the wall of the feed pipe and the tube, and a seal between the wall of the feed pipe and said neck.

9. In combination, a centrifugal bowl rotatable about an axis and having a cylindrical outer wall provided with sludge outlets, the bowl also having an axial outlet for a light component separated in the bowl and a level outlet, located intermediate said central outlet and said sludge outlets, for discharging an intermediate component separated in the bowl, an axial spindle secured to the bowl for rotating the same, the spindle having a passage for supplying feed material to the bowl, a stationary discharge pipe for receiving the light component discharged through said central outlet, a seal between the wall of the 7 stationary pipe and the wallet said central outlet. thesealtforming a closed path through which the light component is discharged from the central outlet to the stationary :pipe, a stationary auxilimy feed pi e, and seals between said last pipe and the walls of said central outlet and level .outlet andfiorming withsaid last walls an auxiliary feed passage leading into the bowl.

IPER HILDING STAAFF.

REFERENCES CITED UNITED STATES PATENTS Name Date Sharples July 3, 1'9'17 Number 2,313,529 2,261,724 2,263,095 22 6; 2,286,355 2,313,540 2,3;13;511 2Ama,-992 2;i85,209 ,2;50n;100

8 vName Date Peltzer Aug. 22 1933 ,Peltzer Nov. 10, 1936 Svensio Aug. 3, 1937 Jones Aug. 3, 1937 Eawcett Sept. 1-9, 1939 Helm .Nov. 4, 1941 Lieberman Nov. 18, v1941 Jones Dec. .16, 1194-1 Fitzimmons June 16, 1942 Hall I Mar. 9, 1943 Flowers Mar. 9, v19 l=3 Wheelwright Aug. 16-, 1949 .Lundal Oct. 18, .1949 :Strezynski Mar. 7, ,1950 

